Search Results (561)

Objective: This article presents a step-by-step digital technique for fabricating a 3D-printed surgical guide to assist in alveoloplasty for immediate denture placement. Methods: The workflow integrates intraoral scanning, virtual tooth extraction, digital soft tissue modeling, and additive manufacturing to produce a customized guide with an occlusal window and buccal slot, along with a verification stent. Results: This method ensures precise ridge recontouring and verification, enhancing surgical predictability and prosthetic fit. Conclusions: Unlike traditional surgical guides based on conventional casts or manual fabrication, this fully digital approach offers a practical and replicable protocol that bridges digital planning and clinical execution. By improving surgical precision, reducing operative time, and ensuring optimal denture fit, this technique represents a significant advancement in guided pre-prosthetic surgery. Full article

Additive manufacturing (AM) has brought significant breakthroughs to the construction sector, such as the ability to fabricate complex geometries, enhance efficiency, and reduce both material usage and construction waste. However, several challenges must still be addressed to fully transition from conventional construction practices to innovative and sustainable green alternatives. This study investigates the use of non-cementitious traditional mixtures for green construction applications through 3D printing using Liquid Deposition Modeling (LDM) technology. To explore the development of mixtures with enhanced physical and mechanical properties, natural pine and cypress wood shavings were added in varying proportions (1%, 3%, and 5%) as sustainable additives. The aim of this study is twofold: first, to demonstrate the printability of these eco-friendly mortars that can be used for conservation purposes and overcome the challenges of incorporating bio-products in 3D printing; and second, to develop sustainable composites that align with the objectives of the European Green Deal, offering low-emission construction solutions. The proposed mortars use hydrated lime and natural pozzolan as binders, river sand as an aggregate, and a polycarboxylate superplasticizer. While most studies with bio-products focus on traditional methods, this research provides proof of concept for their use in 3D printing. The study results indicate that, at low percentages, both additives had minimal effect on the physical and mechanical properties of the tested mortars, whereas higher percentages led to progressively more significant deterioration. Additionally, compared to molded specimens, the 3D-printed mortars exhibited slightly reduced mechanical strength and increased porosity, attributable to insufficient compaction during the printing process. Full article

Addressing the urgent need for lightweight and reusable energy-absorbing materials in aviation impact resistance, this study introduces an innovative multi-directional braided metamaterial design enabled by 4D printing technology. This approach overcomes the dual challenges of intricate manufacturing processes and the limited functionality inherent to traditional textile preforms. Six distinct braided structural units (types 1–6) were devised based on periodic trigonometric functions (Y = A sin(12πX)), and integrated with shape memory polylactic acid (SMP-PLA), thereby achieving a synergistic combination of topological architecture and adaptive response characteristics. Compression tests reveal that reducing strip density to 50–25% (as in types 1–3) markedly enhances energy absorption performance, achieving a maximum specific energy absorption of 3.3 J/g. Three-point bending tests further demonstrate that the yarn amplitude parameter A is inversely correlated with load-bearing capacity; for instance, the type 1 structure (A = 3) withstands a maximum load stress of 8 MPa, representing a 100% increase compared to the type 2 structure (A = 4.5). A multi-branch viscoelastic constitutive model elucidates the temperature-dependent stress relaxation behavior during the glass–rubber phase transition and clarifies the relaxation time conversion mechanism governed by the Williams–Landel–Ferry (WLF) and Arrhenius equations. Experimental results further confirm the shape memory effect, with the type 3 structure fully recovering its original shape within 3 s under thermal stimulation at 80 °C, thus addressing the non-reusability issue of conventional energy-absorbing structures. This work establishes a new paradigm for the design of impact-resistant aviation components, particularly in the context of anti-collision structures and reusable energy absorption systems for eVTOL aircraft. Future research should further investigate the regulation of multi-stimulus response behaviors and microstructural optimization to advance the engineering application of smart textile metamaterials in aviation protection systems. Full article

This study investigates a hybrid manufacturing approach that combines 3D printing and injection molding to extend the limitations of each individual technique. Injection molding is often limited by high initial tooling costs, long lead times, and restricted geometric flexibility, whereas 3D-printed molds tend to suffer from material degradation, extended cooling times, and lower surface quality. By integrating 3D-printed molds into the injection-molding process, this hybrid method enables the production of complex geometries with improved cost-efficiency. The approach is demonstrated using a range of polymeric materials, including ABS, nylon, and polyurethane foam—each selected to enhance the mechanical and thermal performance of the final products. Finite element method (FEM) analysis was conducted to assess thermal distribution, deformation, and stress during manufacturing. Results indicated that both temperature and stress remained within safe operational limits for 3D-printed materials. An economic analysis revealed substantial cost savings compared to fully 3D-printed components, establishing hybrid manufacturing as a viable and scalable alternative. This method offers broad industrial applicability, delivering enhanced mechanical properties, design flexibility, and reduced production costs. Full article

This study presents a microfluidic chip platform designed using a multiscale 3D printing strategy for fabricating microfluidic chips with integrated, high-resolution, and customizable membrane structures. By combining two-photon polymerization (2PP) for submicron membrane fabrication with liquid crystal display printing for rapid production of larger components, this approach addresses key challenges in membrane integration, including sealing reliability and the use of transparent materials. Compared to fully 2PP-based fabrication, the multiscale method achieved a 56-fold reduction in production time, reducing total fabrication time to approximately 7.2 h per chip and offering a highly efficient solution for integrating complex structures into fluidic chips. The fabricated chips demonstrated excellent mechanical integrity. Burst pressure testing showed that all samples withstood internal pressures averaging 1.27 ± 0.099 MPa, with some reaching up to 1.4 MPa. Flow testing from ~35 $\mathsf{\mu }$L/min to ~345 $\mathsf{\mu }$L/min confirmed stable operation in 75 $\mathsf{\mu }$m square channels, with no leakage and minimal flow resistance up to ~175 $\mathsf{\mu }$L/min without deviation from the predicted behavior in the 75 $\mathsf{\mu }$m. Membrane-integrated chips exhibited outlet flow asymmetries greater than 10%, indicating active fluid transfer across the membrane and highlighting flow-dependent permeability. Overall, this multiscale 3D printing approach offers a scalable and versatile solution for microfluidic device manufacturing. The method’s ability to integrate precise membrane structures enable advanced functionalities such as diffusion-driven particle sorting and molecular filtration, supporting a wide range of biomedical, environmental, and industrial lab-on-a-chip applications. Full article

The fabrication of high-performance organic optoelectronic devices using solution-based techniques, in particular inkjet printing, is both a desirable and challenging goal. Organic light-emitting diodes (OLEDs) are multilayer devices that have demonstrated great potential in display applications, with ongoing efforts aimed at extending their use to the lighting sector. A key objective in this context is the reduction in production costs, for which printing techniques offer a promising pathway. The main obstacle to fully printed OLEDs lies in the difficulty of depositing new layers onto pre-existing ones while maintaining high film quality and avoiding damage to the underlying layers. In a bottom-emitting OLED, the electron transport layer (ETL) is the final organic layer to be deposited, making its printing particularly challenging, a process for which only a few successful examples have been reported. In this work, we report on the optimization of a 2,2′,2″-(1,3,5-Benzinetriyl)-tris(1-phenyl-1-H-benzimidazole) (TPBi)-based ink formulation for ETL printing on an emitting layer composed of 5,10-Bis(4-(3,6-di-tert-butyl-9H-carbazol-9-yl)-2,6-dimethylphenyl)-5,10-dihydroboranthrene (tBuCzDBA). A specific ratio of methanol to diethyl ether was identified as the most suitable for printing the ETL without compromising the integrity of the underlying layer. The printed ETL was successfully integrated into an OLED device, which exhibited a maximum current efficiency of 6.8 cd/A and a peak luminance of about 8700 cd/m². These results represent a significant step toward the development of a fully printed OLED architecture. Full article

This work investigated the 3D printing of fully compounded thermoset elastomers using a custom-designed printer capable of processing both thermoplastics and elastomers containing fillers and specific cure packages. The adhesion strength between selected thermoset elastomers and thermoplastic combinations was studied, and the influence of key process parameters on adhesion was evaluated. The results showed that interfacial bonding was favored by the proximity of solubility parameters, the amorphous morphology of the thermoplastic, and increased chain mobility at the processing temperature. Rubber processing parameters significantly influenced adhesion, showing that curing at a lower temperature for a longer duration yielded better results than shorter, higher-temperature cures. Elemental analysis revealed the presence of rubber-specific components on the thermoplastic surface, suggesting interfacial migration. These findings contribute to advancing multi-material 3D printing by enabling the integration of rubber-like materials with thermoplastics, expanding opportunities for applications in high-temperature and chemically demanding environments. Full article

Batteries are used as energy storage devices in various equipment. Today, research is focused on solid-state batteries (SSBs), replacing the liquid electrolyte with a solid separator. The solid separators provide electrolyte stability, no leakage, and provide mechanical strength to the battery. Separators are mostly manufactured by either traditional processes or 3D printing technologies. These processes involve making a slurry of plastic, active and conductive material and usually adding a plasticizer when making thin films or filaments for 3D printing. This study investigates the additive manufacturing of solid-state electrolytes (SSEs) by employing fused deposition modeling (FDM) with recyclable, bio-derived polylactic acid (PLA) filaments. Precise control of macro-porosity is achieved by systematically varying key process parameters, including raster orientation, infill percentage, and interlayer adhesion conditions, thereby enabling the formation of tunable, interconnected pore networks within the polymer matrix. Following 3D printing, these engineered porous frameworks are infiltrated with lithium hexafluorophosphate (LiPF₆), which functions as the active ionic conductor. A tailored thermal sintering protocol is then applied to promote solid-phase fusion of the embedded salt throughout the macro-porous PLA scaffold, resulting in a mechanically robust and ionically conductive composite separator. The electrochemical ionic conductivity and structural integrity of the sintered SSEs are characterized through electrochemical impedance spectroscopy (EIS) and standardized mechanical testing to assess their suitability for integration into advanced solid-state battery architectures. The solid-state separator achieved an average ionic conductivity of 2.529 × 10⁻⁵ S·cm⁻¹. The integrated FDM-sintering process enhances ion exchange at the electrode–electrolyte interface, minimizes material waste, and supports cost-efficient, fully recyclable component fabrication. Full article

Three-dimensional food printing (3DFP), a specialized application of additive manufacturing (AM), employs a layer-by-layer deposition process guided by digital image files to fabricate edible structures. Utilizing heavily modified 3D printers and Computer-Aided Design (CAD) software technology allows for the precise creation of customized food items tailored to individual aesthetic preferences and nutritional requirements. Three-dimensional food printing holds significant potential in revolutionizing the food industry by enabling the production of personalized meals, enhancing the sensory dining experience, and addressing specific dietary constraints. Despite these promising applications, 3DFP remains one of the most intricate and technically demanding areas within AM, particularly in the context of modern gastronomy. Challenges such as the rheological behaviour of food materials, print stability, and the integration of cooking functions must be addressed to fully realize its capabilities. This article explores the possibilities of applying classical modified 3D printers in the food industry. The behaviour of certain recipes is also tested. Two test case scenarios are covered. The first scenario is the work and formation of a homogenized meat mass. The second scenario involves finding a chocolate recipe that is suitable for printing relatively detailed chocolate decorative elements. The current advancements, technical challenges, and future opportunities of 3DFP in the field of engineering, culinary innovation and nutritional science are also explored. Full article

This study investigates the initial consonant system of the Yongle Nanzang 永乐南藏, the second officially printed edition of the Chinese Buddhist canon of the Ming dynasty, and its relationship to the Qishazang 磧砂藏. Based on a digital and quantitative analysis of 27,832 phonetic entries—including Fanqie 反切 and Zhiyin 直音—we apply correlation coefficients (with significance tests), hierarchical clustering, and data mining methods. The results show the following: (1) In the labial series, contrasts between aspirated and unaspirated sounds are weak; Bang 幫 and Pang 滂 are occasionally confused; and Fei 非 and Fu 敷 are merged. Voiced and voiceless initials are sometimes mixed, but full devoicing has not occurred. (2) In the coronal series, Duan Zu 端組 shows high internal interchange and Zhi Zu 知組 tends to mix with Zhang Zu 章組 and Zhuang Zu 莊組. (3) In the sibilant and affricate series, Jing 精 and Zhuang 莊 are merged; Chuan 船 and Shan 禪 also merge, while Cong 從 and Xie 邪 only occasionally alternate. (4) In the velar and laryngeal series, fully voiced Qun 羣 is close to voiceless initials, while Yun 云 and Yi 以 are closely related. Nasal and lateral initials maintain independence. The findings suggest that Yongle Nanzang 永乐南藏 is not a direct reprint of the Qishazang 磧砂藏, but rather a revised edition adapted to editorial or regional considerations. This study demonstrates the value of digital phonological methods in historical phonology and the significance of the Ming–Qing Chinese Buddhist canon. Full article

Stained glass has played important roles in heritage building construction, however, conventional fabrication techniques have become economically prohibitive due to both capital costs and energy inefficiency, as well as high-level artistic and craft skills. To overcome these challenges, this study provides a new design methodology for customized 3D-printed polycarbonate (PC)-based stained-glass window alternatives using a fully open-source toolchain and methodology based on digital fabrication and hybrid crafts. Based on design thinking and open design principles, this procedure involves fabricating an additional insert made of (i) a PC substrate and (ii) custom geometries directly 3D printed on the substrate with PC-based 3D printing feedstock (iii) to be painted after the 3D printing process. This alternative is intended for customizable stained-glass design patterns to be used instead of traditional stained glass or in addition to conventional windows, making stained glass accessible and customizable according to users’ needs. Three approaches are developed and demonstrated to generate customized painted stained-glass geometries according to the different users’ skills and needs using (i) online-retrieved 3D and 2D patterns; (ii) custom patterns, i.e., hand-drawn and digital-drawn images; and (iii) AI-generated patterns. The proposed methodology shows potential for distributed applications in the building and heritage sectors, demonstrating its practical feasibility. Its use makes stained-glass-based products accessible to a broader range of end-users, especially for repairing and replicating existing conventional stained glass and designing new customizable products. The developed custom patterns are 50 times less expensive than traditional stained glass and can potentially improve thermal insulation, paving the way to energy efficiency and economic savings. Full article

Background: Autogenous tooth transplantation is a valuable option for dental rehabilitation, particularly in young patients. Template-guided approaches, using 3D-printed replicas of donor teeth, have recently emerged as a method to increase precision and reduce extraoral time—two critical factors in maintaining periodontal ligament (PDL) vitality, which is essential to improve long-term outcomes. Methods: This report presents the case of a 12-year-old patient who underwent autotransplantation of tooth 18 to the site of tooth 75, which exhibited ankylosis. Patients exhibiting unfavorable root anatomy and morphology, systemic conditions, or completed root development were not considered for this technique. A patient-specific donor tooth replica was digitally designed and 3D-printed via CAD/CAM manufacturing to preoperatively shape the recipient site. The transplanted tooth 18 was then inserted with an extraoral time of less than one minute and subsequently stabilized using a flexible titanium trauma splint (TTS). Results: Longitudinal clinical and radiographic follow-up over 12 months confirmed favorable healing without signs of complications. Conclusions: This case illustrates the practical advantages of a fully digital, template-guided workflow in managing anatomically complex cases. Full article

This paper investigates the measurement capability, dynamic response, and mechanical reliability of all 3D-printed multi-material thermistors. The thermistor design consisted of three main components: a polycarbonate (PC) substrate, a silver (Ag) electrode pair, and a poly(3,4-ethylenedioxythophene):poly(4-styrenesulfonate) (PEDOT:PSS) thermosensitive layer. The thermistors were fabricated using two manufacturing techniques: fused deposition modeling (FDM) for the substrate and micro-dispensing for the Ag and PEDOT:PSS films. Two designs with different sensing areas, D1 (90 mm²) and D2 (54 mm²), were fabricated. As the indicator of measurement capability, the highest thermal indexes were recorded as 905.64 and 813.03 K for D1 and D2 thermistors, respectively. Thermistors exhibited comparable dynamic performance, with normalized resistance variations ranging from 0.96 to 1 for temperature changes between 25 and 45 °C. The sensing area influenced both measurement capability and dynamic performance, where larger sensing areas enhanced measurement capability but extended the time required to complete dynamic cycles, around 400 s for D1 versus 350 s for D2. Adhesion tests revealed a strong bonding between the PEDOT:PSS and Ag layer with less than 5% material removal. However, the adhesion of the PEDOT:PSS to the PC substrate was weak, with over 65% material removal. Morphological analysis indicated that the poor adhesion was caused by suboptimal surface properties of the 3D-printed substrate, even resulting in gaps between these two surfaces. This study demonstrates that our all 3D-printed multi-material thermistors can match reported measurement performance with an acceptable dynamic performance while highlighting the need to improve 3D-printed substrate surface properties to enhance the performance of such multi-material structures. Full article

This paper presents a case study comparing CFD predictions with experimental measurements for micropumps, with the goal of evaluating the accuracy and limitations of CFD methods in complex microscale geometries. A fast design and evaluation methodology was developed, integrating linear design, 3D fully viscous CFD-based optimization, and rapid prototyping and testing. The main problem at this scale and configuration of pumps is the combination of Reynolds and Taylor numbers. Their impact on labyrinth performance prediction and therefore volumetric efficiency dominates the losses at this scale. Multiple CFD simulations were conducted using various turbulence models and solver settings, and results were compared against experimental data. The labyrinth region was simulated both independently and as part of the full pump assembly, with RANS and LES used for the former and RANS for the latter. Precision 3D-printed rotors and volutes were tested, and performance maps were obtained. Significant discrepancies between CFD and experiments were observed, which were reconciled using two empirical scaling coefficients for pressure and mass flow. These collapsed the CFD predictions onto the experimental data across all available speedlines. While the generalizability of these coefficients remains uncertain, the concept of using corrected scales, rather than other methods, seems to capture the macroscopic discrepancies between CFD and experiments. Full article

Compared to traditional manufacturing methods, additive manufacturing (AM) enables the production of parts with arbitrary structures, effectively addressing the challenges faced when fabricating complex geometries using conventional techniques. The dynamic development of this technology has led to the emergence of increasingly advanced materials. One of the best examples is metal–polymer composites, which allow the manufacturing of fully dense components consisting of stainless steel and titanium alloys, employing the widely available AM technology based on material extrusion (MEX). Metallic materials intended for this type of 3D printing may serve as an alternative to currently prevalent techniques including techniques like selective laser melting (SLM), owing to significantly lower equipment and material costs. Particularly applicable in low-volume production, where total costs and manufacturing time are critical factors, MEX technology of polymer–metallic composites offer relatively fast and economical AM of metal components, proving beneficial during the design of geometrically complex, and low-cost equipment. Due to the significant advancements in AM technology, this review focuses on the latest developments in the additive manufacturing of metallic components using the MEX approach. The discussion encompasses the printing process characteristics, materials tailored to this technology, and post-processing steps (debinding and sintering) necessary for obtaining fully metallic MEX components. Additionally, the article characterizes the printing process parameters and their influence on the functional characteristics of the resulting components. Finally, it presents the drawbacks of the process, identifies gaps in existing research, and outlines challenges in refining the technology. Full article